Our underlay rolls cover 15.07 square metres; simply multiply your length by your width (to get the total square meters), and divide it by 15.07 and you will know how many rolls of underlay you will need.
Shingles, tiles, and underlayment are sold in what the industry calls “squares.” Each square is equal to whatever the calculated square footage of your roof is, divided by 100 e.g. 1340 square feet = 13.4 squares. Don't forget to measure any overhangs or eaves, as they contribute to the roof's total square footage.
More is not always better, and with underlayment, too much can compromise the integrity of your floor's locking system. Adding additional underlayment under vinyl with an attached pad can create too much cushioning, which causes the floor to come apart through use over time.
Typically you might need 100mm or 150mm of turf underlay (0.1 or 0.15 metres). Example 1 – You have a rectangle measuring 10m x 6m and need to add 100mm of turf underlay soil. 10m x 6m x 0.1m = 6m3. Example 2 – You have a circular area with a diameter of 14 metres and a radius of 7 metres, needing 150mm of soil.
Calculate the Underlayment Needed
If you go with type #15, you will need one roll per four squares, meaning 3.9 rolls for 15.6 squares. The pitch of the roof can affect how much underlayment you need. If you have a roof with a pitch greater than 4/12, a single layer is enough.
Our underlay rolls cover 15.07 square metres; simply multiply your length by your width (to get the total square meters), and divide it by 15.07 and you will know how many rolls of underlay you will need.
Choosing a thick (10mm+) underlay for your stairs is not a good idea as it can pose a trip hazard. Moreover, thicker carpet underlays tend to compress slightly with heavy use, which can lead to irregular wear and unsightly lumps, particularly in frequently trodden areas.
A 3mm underlay is ideal for flooring less than 18mm thick. This thinner option provides sufficient support without adding unnecessary height. For flooring that is 18mm or thicker, you'll need a 5mm underlay. This added thickness ensures better stability and cushioning for heavier or more robust flooring options.
By rolling your lawn once it has been laid in its entirety you will reduce these uneven levels. Consequently, this will save you the need to top-dress the area in the future to correct these uneven levels. This is just one of the reasons why rolling turf after laying is important.
Quantity of Top Dressing Soil
If this is being done purely to smooth the lawn then you can apply at 3 to 4 kilos per square metre which will give about ¼” or just over half a centimetre in depth. Obviously, the dips will get more, but you must not smother the grass. The rule is 75% of the leaf must be exposed.
Too much padding can make the floor too bouncy, which strains the laminate's locking system. If you are fitting a laminate floor with a pre-attached underlay to concrete though, it's a good idea to install a vapour barrier as well. This will help prevent moisture damage.
Other factors like type, sound ratings, and density matter just as much, if not more than the thickness. With that being said, most underlayments are 2-3mm thick, but are sometimes thicker for carpet or to smooth out an uneven subfloor.
Felt underlayment should overlap the edge metal at the eaves and be overlapped by edge metal on the rakes. This is also true for rubberized asphalt underlayment, but not necessarily true for synthetics. Asphalt-saturated felt may fail for a number of reasons.
Advantages of Levelling Compound Subfloor. 1. It Can Level Anything: Whether your subfloor is currently made of concrete or plywood or any other material, chances are a self-levelling can be poured over the top to it to create a smooth and level finish.
3 in 1 underlayment is typically a thin foam pad used under floating floors, usually created from either polyethylene or polypropylene. It most often comes in rolls of 100 to 200 square feet and is rolled out onto the sub-floor before the hardwood, laminate, and vinyl tile flooring is laid down.
Flatten any lumps and bumps and fill in any hollows. Rake the soil to break it up and create a level surface. Tread the area thoroughly - get the whole family involved to cover the area quickly!
Roll each area slowly and carefully just once. Excessive rolling will damage the sod instead of helping it. Rolling eliminates any gaps, loose soil, or air pockets that prevent roots from reaching the soil and getting a good grip as they grow.
For example, one of our most popular products – the Plushwalk 12mm Carpet Underlay – comes in half rolls containing 7.5m2 and full rolls containing 15.07m2 of underlay. To work out how many you need, divide the total surface area of your room (e.g. 100m2) by 15.07 and round up to the nearest half or full roll.
Expansion gaps should be left around the perimeter of the floor around 10-12mm.
Impact on Flooring Warranty:
Many flooring manufacturers specifically advise against using more than one layer of underlay, as this can void the product's warranty. The extra cushioning places unnecessary stress on the locking mechanisms and joints of the floor, making it more likely to fail prematurely.
No subfloor is perfectly level, but any signs of unevenness and high or low spots must be remedied. Please follow these requirements: Subfloor unevenness cannot be greater than 3/16 of an inch over a 10-foot span or 1/8 inch over a 6-foot span. Subfloors must not slope more than ½ inch per 6 feet (25 mm per 1.8 m)
Tip: Make sure the two white sides are as close as they can be and lay one over the other and tack it down. That is how you will know if it's on upside down -- if the tape strip is down, it is backwards. It is very important that the underlayment run the same direction as the flooring.
Butt the seams together, leaving no gaps or overlaps. Roll the underlayment with a maximum 35-pound roller to fully bond the adhesive. First, roll in a north-south direction and then repeat in an east-west direction.